fool's mate

The diagram in post #1 is not checkmate (because 4. Qxf7# has not been played yet), but that would be an incoming Scholar's mate, not Fool's mate.

Fool's Mate -- shortest checkmate (f-pawn could also be on f4)

Or one ply longer from white's perspective.

Martin_Stahl is right.  I have fallen victim to both.  I received Scholar's Mate from a four year old when I was I my thirties and had to pay the kid £20.  Scholar's mate is called scholar's mate because everybody falls for it at least once.  Fool's mate is rarer, and many never encounter it in a real game.  I, however, have also fallen for it, and still remember my father's smirk as he checkmated me on his second move.  Not good.

Pity the fool.